Telegraph system



June 15 1926. 1,588,450

S. l. CORY TELEGRAPH SYSTEM Filed Oct. 9., 1924 INVENTOR ATTORNEYPatented June 15, 1926.

UNITED STATES I 1,588,450 PATENT OFFICE".

SAMUEL'I. CORY, OF ELMHURST, NEW YORK, ASS'IGNOB TO AMERICAN TELEPHONEAND TELEGRAPH COMPANY, A. CORPORATION OF NEW YORK.

TELEGRAPH SYSTEM.

Application filed October 9, 1924. Serial No. 742,589.

This invention relates to telegraph systems, and particularly tohalf-duplex'telegraph systems.

In the former arrangements of half-du- 5 plex systems, a plurality ofauxiliary circuits areused to connect up the main branches of the systemwhich consist of the receiving polar relay circuit and the pole changingrelay circuit for half-duplex oper ation. By the arrangements of thisinvention means are provided in the local circuits of repeaters topermit half-duplex operation without entailing the use of the auxiliarycircuits of the former arrangements. The operating features aresubstantially the same as in the former arrangements, while theoperating charges are greatly reduced, due

to the elimination of the current drain in the auxiliary circuits.

be applied to radio, carrier systems, and ,direct current groundedtelegraph systems. For the purpose of illustration, however,

this invention has been applied to a bridge polar duplex system.

The novel features which are characteristic of. the invention are setforth in the appended claims. The invention itself, however, both as toits organization and method of operation, will be best understood byreference to the following description taken in connection with theaccompanying drawing in which is indicated diagrammatically one way inwhich the invention may be carried into effect.

In describing the operation of'the illustrated system, let it be assumedthat the main line conductor L connects the terminal station representedin the diagram with another station at the distant end of said line.Opening and closing of the key K causes an opening and closing of theloop circuit consistin of grounded battery 13,, resistance 73,

the winding B of the neutral, non-polarized relay E, the armature 1 ofthe control relay C, the winding of the repeating sounder N, the loop,the resistance r, and battery 13,. Current through winding B of theneutral, non-polarized relay E will, of itself, besuflicient to hold thearmatures 3 and 4: of said relay in their closed positions. Thearmatures 3 and i, as well as the armatures 1 and 2 of the control relayC, move synchronously, being connected by a link of insula- Thearrangements of this invention may,

the winding of the pole changer P, key K,-

tion. It the armatures of relay E are held in their closed positions,the opening and closing of the circuit just described will move thearmature of the pole changer P between the spacing and marking contactsS and M to alternately connect the spacing battery B and the markinbattery B to the apex of windings c and Current from batteries '15, or Baccordingly divides, one portion as would be the case during thereception of marking and spacing signals over line L from the distantstation, a receivlng circuit is controlled by said armature consistingof grounded battery 13,, resistance 1' the armature of relay R,conductor '2), winding A of relay E, the winding of control relay C andresistance 1",. When the armatures of relay E are in their openpositions, conductor x will short-circuit Winding A in the circuit justdescribed. As the circuit that includes the winding of control relay Cis made and broken, the armatures of relay C are alternately moved fromtheir closed to their open positions, producing signals in the repeatingsounder N, said sounder being used for monitoring purposes. I

The arrangements of this invention operate in the following manner: Tosend signals over line L, the key K, which is in series With the loop,is operated. For a marking signal, key K is depressed, and the armatureof the pole changer P connects marking battery B through armature 3 ofrelay E to the line L; and for a spacing signal, the spacing battery Bis connected to the line L. During the time that signals are being transmittedover line L, the armatures of relay E are held in their closedpositions, because current is flowing through winding A in the 'circuitfrom battery B resistance 1' the the armatures of relay E closed whencurrent flows through said winding, and the armatures of relay E arethereby held in their closed positions during the transmission ofsignals over line L. When receiving signals from the station at thedistant end of line L, the operator keeps key K closed. VVhen a spacingsignal comes over line L, the. armature of relay R moves to its spacingcontact S. The circuit, extending from battery B is opened, and nocurrent flows through the winding of control relay C, and therefore thearmatures of said relay are moved to their open positions. The circuitin series with the loop is therefore opened at armature 1, and the polechanger P is de-energized so that its armature moves to its spacingcontact. The circuits through both windings A and B of relay E are thusopened, the one at the armature of receiving relay R and the other atarmature 1 of relay C. Hence, the armatures of relay E are released.Armature 3 of relay E connects the marking battery B, to line L throughthe conductorw, so that the marking polarity at the pole changer P isnot interrupted, except during the time it takes the armature 3 of relay-E to reach its open position. During this. armature travel time thecondenser Z discharges and minimizes the effect upon the signalsproduced by the momentary opening of the circuit just mentioned.Armature 4 of relay E connects conductor w so as to short-circuitwinding A for a purpose which will appear hereinafter. i v

When a marking signal arrives at the station, the armature of thereceiving relay R closes, and the control relay C operates due tocurrent from battery B Consequently,

the circuit in series with the loop is closed. Current through thewinding of the pole changer P- will move the armature to the markingcontact M. U to this time winding A of relay E has een short-circuiteddue to the parallel path through conductor :12, and the armature 4 ofrelay E. However, relay B will now operate due to the flow of currentthrough the winding B. The purpose of short-circuiting winding A is todelay the operation of relay E until after the control relay C and the.pole changer P have operated. If relay E operated before the polechanger P, there would be a short period of time during which a spacingimpulse would be transmitted to line L. i

If, when the operator at the station is transmitting and the distantoperator attempts to break, the key K is open, the incoming breakingsignal will move the armature of the receiving relay R to its spacingcontact S but will not open up the circuit including the wind-in of thecontrol relay C and battery B,. T is is accomplished by providingparallel paths from battery B to the winding of the control relay C, onepath through the armature of relay R to conductor '0, and the otherthrough conductor a, the armature of the sounder N, armature 2 of thecontrol relay C, conductor t to conductor 0. Consequently, when thearmature of relay R 'is opened due to a breaking signal, if the loopcircuit is open at key K, the sounder N will be released, and thewinding of the control relay C will still receive current from battery Bdue to the parallel path established by conductors u and t, as justexplained But just as soon as key K is closed the sounder N will bere-energized, opening the parallel path through relay C, so the relay Creleases its armature and opens the loop circuit. Consequently, theoperator will realize that a breaking signal is being transmitted as thefurther opening and closing of the key K is ineffective to transmitsignals.

Although oneembodiment of the invention has been described, it is to beunderstood that the invention is not limited to any specificconstruction but might be embodied in various systems without departingfrom the spirit of the invention or the scope of the appended claims. I

What is claimed is: I

1. In a telegraph system, in combination, a main line, an artificialline, a sending leg, a receiving leg, a subscribers loop, a relayinterlocking said sending and receiving legs and said subscriber7s loop,said relay havin two armatures and two windings, one winding beingserially arranged in said sending leg and the other winding beingserially arranged in said receiving leg, one armature shunting a windingof said relay serially arranged in said receiving leg and the otherarmature connecting batteries of opposite polarity to the main line, acon- I trol relay having two armatures, one armature controlling thesending leg and the other armature also shlinting thewinding of theinterlocking relay serially arranged in said receivingleg', and arepeating soundsaid armatures short-circuiting one winding of said relayin the receiving circuit, the

other armature connecting the armature of the pole changing relay withthe main line,

a control relay having its winding serially arranged in thereceivingcircuit, one armature of the control relay controlling the sendingcircuit, the other armature of the control relay moving synchronouslytherewith and forming a ath so as to shortcircuit the armature o thepolar relay, and

'a repeating sounder operated by incoming and outgoing signals.

3. A telegraph system comprising a main line, an artificial line, areceiving relay actuated by signals from the distant station andcontrolling-the receiving circuit of said main line, a pole changingrelay alternately connecting oppositely poled batteries to said mainline, a key controlling the sending circuit, a loop, a neutral,non-polarized relay having two windings, one of said windings beingserially arranged in said sending circuit and the other seriallyarranged in said receiving circuit, a control relay having the windingthereof serially arranged in said receiving circuit, one armaturecontrolling the a, sending circuit, and the other moving synchronouslytherewith and forming a path so as to short-circuit the armature of saidreceiving relay, and a repeating sounder actuated by signals bothtransmitted and received.

4. A. telegraph system comprising a main line, an artificial line, apolar relay responsive to incoming and non-responsive to outgoingsignals 1n said main line, a pole changing relay, the armature of saidrelay alternately connecting to said main line batteries of equalpotential and opposite polarity, a loop, a key operating the send ingcircuit, a neutral non-polarized relay having two windings and twosynchronously moving armatures, one of the windings being serlallyarranged in the sending circuit and the other winding being seriallyarranged in the receiving circuit, one of the armatures short-circuitingthe winding of the neutral non-polarized relay serially arranged in thereceiving circuit, the other armature connecting the armature of thepole changing relay to the main line, a control relay having twosynchronously moving armatures, one armature controlling the sendingcircuit, the other armature forming a path so as to short-circuit thearmature of the polar relay, and a grounded condenser connected to' themain line. I

In testimony whereof, I have signed my name to this specification this7th day of' October, 1924.

SAMUEL I. CORY.

